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Topic: Is Continous Autofocus a big deal for those who shoot video (Read 22012 times)

I think it would be very useful especially for personal use. I agree it would never replace manual focus for professional use, but for personal use it would be very useful. Personally not being very skilled at manual focusing I end up using my 24mm stopped down for most of my family video to benefit from a longer DoF and having more of the scene in focus...maybe this is why Canon came out with a 24 and 28 IS prime lens!

jrod

“At the end of the day it is a still camera with video functions” - Think twice before promoting it like that. Might just be that kind of shortsighted propaganda, which pisses customers off. Nikon did it, Panasonic did it, … “Everything requires some tradeoffs.” For sure that ignorant kind of wise guy talking; - claiming it would not be possible without infringing with the photo-functions,- will cause some major tradeoffs. Are you claiming, that while performing 6 frames per second on a fast moving object your camera does not keep the object in focus? Are you claiming that the canon video cameras do not catch up the focus on moving objects? Your next consumer DSLR will anyway be obliged to carry an Autofocus system for video. How will you promote that? “Not for professionals” Arrogance does not sell!

I think you miss the point of my post, I am not saying auto focus is a bad thing or that its "not for pros". What I am saying is that the engineering of a proper auto focus system would require compromises to the imagining, lens design, and focus algorithms that were all designed to the best performance on a "still" camera.

Lets take your example of shooting 6fps, or heck lets say we are using a 1DX and shooting 12fps. The focus system is design to quickly achieve focus, snap a picture, then achieve a new focus again. Each frame is a new focus event, how quickly or violently it changes focus between these events has no effect on the picture as each is an individual event. Most people will tell you when tracking a moving subject all 12 frames are not always in focus, 1 or 2 might be missed. Think of what this would do to your eye if just 1 out of every 30 frames of video were out of focus, I know it would give me a massive head ache.

The motors in still lenses are not engineered for slow rolling focus that is done in video/film, they are designed to get from one focus point to the next as quickly as possible. This is why some lenses focus faster than others and some bodies focus faster than others. It works amazingly well for still shots. But when you try to do this with video it is not pleasing to the eye, with focus moving too fast and sometimes in a psychotic fashion, video or film require liquid smooth focus changes. In the end it is much more than shooting 30 or 60fps, it is about each frame flowing into the next to make a smooth picture.

I would suggest that people take a look at videos of nikon and sony's DSLRs and how the focus changes when using the auto focus (and real videos not the company produced ones). They may support the feature on paper, but the visual quality in how they change focus is worse than just about any $200 camcorder. Not to mention the noise from the lens changing focus.

Now if Canon wants to bring out a "video" lens and build in a focusing algorithm to support it that would be great, and they may be working towards this with their C line. Now the video lens would be very slow for focusing still shots, but would look beautiful in video. Again there is a reason no one has perfected the still/video + autofocus camera, the trade offs must be weighted. And like I said before Canon choose to design the camera and lenses to be a still camera first and a video camera second. This is is just the nature of the engineering, all political and marketing aside.

Personally, with the shallow depth of field nature of dslrs in video, i wouldn't trust autofocus to get the focus just right and always prefer to pull focus myself. Especially with the high density and sharp displays on the 60d t2i and t3i. much nicer to pull focus on than 5dmkii and 7d.

Jedifarce

For me, I would love to have autofocus. I shoot with my 5D2 and 7D on a Steadicam. And since I don't have a Spielberg budget, I don't have wireless remote monitoring and a focus puller on my staff, autofocus on a Steadicam would be great.

Sure it wouldn't be perfect, but it would give me a fighting chance in low light situations where I can't stop down the lens.

I'm not sure why you would need a focus puller when you're only using a steadicam or how autofocus would help in low light situations. Low light has more to do with your f/stop, iso and shutter speed than your focus.

« Last Edit: March 21, 2012, 03:22:21 AM by Jedifarce »

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Jedifarce

I'm just perplexed by the people saying this feature will need to be included in future large sensor cameras - it sounds like a lot of still photographers that dabble in video - to my way of thinking it's like saying all still cameras in the future should include a feature that automatically frames the photo correctly - how could the camera possibly know what's correct?

I'm sure you'll find that it's people that come from a camcorder background and have yet to or simply haven't shot any video on a DSLR in manual mode. Just ask them if they have a follow focus - probably not, external monitor - doubtful, that should tell you something about their position.

I'm not sure why you would need a focus puller when you're only using a steadicam or how autofocus would help in low light situations. Low light has more to do with your f/stop, iso and shutter speed than your focus.

I'm not sure why you would need a focus puller when you're only using a steadicam or how autofocus would help in low light situations. Low light has more to do with your f/stop, iso and shutter speed than your focus.

Ummm...that's the opposite of autofocus - that's a wireless follow focus. This is designed so that a focus puller can operate it without touching the camera - vital for some types of crane/jib work and especially (because I am a steadicam operator) steadicam work where focus is impossible without such devices.

Not at all, I wouldn't want it and I suspect it would cause more trouble than it's worth, and video is really all I do with DSLRs. People have been using MF in the cinema industry for as long as it's been around, I don't think any professionals will be disappointed in the slightest bit.

If it's always been done that way, clearly it's the best and only way.Hollywood was never in danger of becoming obsolete until now, so their failure to innovate was never an issue.When film costs as much as a house, every second is precious.They've mastered the distribution of each role in producing a marketable product.

You still need actors, direction, sets, costumes, visual effects, grading, editing, sound, and music.But the ability to capture raw material has been revolutionized.Computers/software have revolutionized what one intelligent person can do in post.

Movie AF, if stopped down, could be a vital feature for one-man steadycam/crane work.At the very least (and I've said this 1,000 times now), stutter-free follow focus controller.

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"There is no good and evil. There is only power, and those too weak to seek it."

Ummm...that's the opposite of autofocus - that's a wireless follow focus. This is designed so that a focus puller can operate it without touching the camera - vital for some types of crane/jib work and especially (because I am a steadicam operator) steadicam work where focus is impossible without such devices.

Depends on your options....There was also a pieces to get distance and can be used to autofocus; At least I saw one early demo that was being shown that way. But yes, it was really designed around wireless follow focus.

Eh, I just think people read all these fancy words on blogs and forums, an spout them out like they know what they are talking about.

Personally, I've never had a client complain about the resolution of my images... (I currently shoot with a T2i)...Never had an issue getting an awesome final product, easily and efficiently.

Even if... the 5d3 gives me an identical resolution... I'm buying it because of the Full Frame.... and the Autofocus...

I really REALLY think all the whiners on this site have no idea how to properly process a file.(and don't give us the BS that no one can process the RAW file yet because no one supports it... that's just a lame excuse for people who don't know what they are doing).

Oh.. and just for a point of reference for all you gearhead pixel peepers...Compare any iso800 file from ANY Nikon or Canon camera made in the last 2 years... and compare it to what ISO 100 looked like 3 years ago......People werent' complaining then...

Not One Bit. In a Good production, A camera requires a dolly/Stedicam Operator and a focus puller minimum for good camera work. Along with the careful selection of lenses, lighting, and a competent DP, a Three Man crew is good enough for small productions.

For consumer video, sure! auto-focus would be great but they might look towards offerings from sony for that. (a77)

The Canon XF100/105/300/305 are all marketed as "professional" camcorders. For $3000 to $8000, they certainly don't seem targeted at the kiddie's birthday party market. And all of them have autofocus capability, and it's apparently fairly sophisticated. (They also have built-in lenses and fairly small sensors.) If "professionals" use manual focus, why is this capability included in these models?

3000-8000$ is nothing in a good sized production but that's not my point. If you want to shoot FILM, you will need an arri-cam operator and a focus puller. The advantage of film is it's large size compared to tiny video chips. That's why the Alexa and RED are doing so well. They don't need all the logistics of feeding film to the camera and also have the advantages of sweet interchangeable lenses from zeiss, Cooke, and arri. Along with a large sensor...

we have used canon XL1's before and I was a good cam for its day. Pro video cameras with AF have large DOF for ease of autofocus to gently transition focus. It's great for TV productions, it's great for solo stedicam operators , it's great for alot of things. But it doesn't offer complete creative control that shooting with an interchangeable system as large as canons EF or a true PL system offers, let alone zeiss supports too.

Thats why the 5D2 is awesome because it HAS a large sensor and it CAN change lenses and CAN do these things cheaper.